First Principles Hartree-Fock Cluster Study Of Very Dilute Transition Metal And Rare-Earth Ion Systems In Silicon

The locations and electronic structures of dilute Mn2+ and Er3+ impurity ions in silicon are studied using the Hartree-Fock Cluster procedure including relaxation in the positions of neighbors of the impurity ions. Three likely sites are studied, hexagonal intersititial (H i), tetrahedral interstitial (Ti) and substitutional (S). Of these, Hi is found to be unstable and S has larger binding energy than Ti, the latter being found to be the occupied site by channeling measurements. This is also supported by the agreement between our theoretical result and experiment for the Mn2+ ion magnetic hyperfine constant. A possible reason for the observation of the Ti site experimentally is suggested. © 2008 American Institute of Physics